The invention relates to a test device, a test system and a method for testing a power engineering test object. In particular, the invention relates to a test device, a test system and a method for testing and checking, respectively, operating resources in electrical high voltage or medium voltage systems, such as power transformers, current converters, voltage converters, circuit breakers, generators, motors or cable systems, protection relays, etc.
Modern test devices for operating resources in electrical high voltage and medium voltage systems usually comprise a processor or a controller which calculates a desired signal waveform for a test signal, e.g., a variable sinusoidal signal waveform, a digital-to-analog converter for converting the thus generated signal waveform into an analog test signal, and an amplifier for amplifying the test signal to, thereby, obtain the test signal with a desired amplitude.
However, depending on the choice of the components used in the respective test device, the respectively obtainable amplitude range is limited. Therefore, in conventional test environments, separate external amplifiers are used for certain applications, which are supplied with the respective test signal and output the thus amplified test signal to the respective test object. However, such separate external amplifiers, whose functionality is limited to the amplifier functionality, increase the costs associated with the test system and the test environment, respectively.
It is therefore the object underlying the present invention to provide a possibility to expand the range of application of a test environment with simple means and to be able to test a power engineering test object with an increased amplitude range.